The disclosure relates to a monitoring system that monitors a monitoring target area using captured images of the monitoring target area, a monitoring method, a monitoring program, and a recording medium in which the program is recorded.
Nowadays, a monitoring system in which a face recognition technology is used is becoming popular. JP 2007-158421 A discloses an example of the face recognition technology. In the monitoring system, a face feature quantity of a person of a monitoring target is previously stored in a storage, a face area is detected from an input image input from a monitoring camera, a feature quantity is extracted in each face area, the extracted feature quantity is compared to and matched against the face feature quantity stored in the storage, thereby detecting the person of the monitoring target.
When the monitoring system is constructed with a plurality of imaging devices, not only the monitoring is performed at one place, but also when and where the person of the monitoring target exists can be detected at a plurality of places, which allows analysis of a line of movement of the person of the monitoring target.
In the monitoring system, the face feature quantity of the person of the monitoring target is previously stored as a face feature quantity list in the storage, and there is an advantage that a monitoring task can automatically be performed without visual management of an observer. Therefore, the monitoring system is used in not only the monitoring of a suspicious person but also a trend analysis of other persons, such as a good customer in a store.
However, in the monitoring system, with increasing number of persons of the monitoring targets, the number of face feature quantity subject to the matching increases, and therefore unfortunately a load necessary for matching processing and processing time also increase. In practice, this problem should be solved.
An object of the disclosure is to efficiently perform the matching processing even if many possible persons of the monitoring targets exist.